Your points are spot on.
Highlight correction is subtle but useful in that it reduces the point at which highlights get clipped. Mine is almost always on, except if I want to use ISO 100 to get a long shutter-speed and I don't have an ND filter with me.
Shadow correction makes images look flat and reduces contrast. I never use it.
You can play with shadow and highlight contrast if you want an even more subtle effect but I found the defaults ideal in most cases.
- Itai
Neoluminance | Fine Art Photography